To fix this issue, start by checking your internet connection (Wi-Fi or mobile data). Then go to Settings > Mail > Accounts > Fetch New Data and enable Push or set Fetch to automatic. Restart your iPhone and ensure Background App Refresh is turned on. You can also remove and re-add your email account to refresh settings. Updating to the latest iOS version helps fix bugs, and if the issue persists, resetting network settings can restore proper syncing. Know more about iPhone Mail not updating